CN204859178U - System for restrain power consumption information collection system interfering signal - Google Patents

Abstract

The utility model provides a system for restrain power consumption information collection system interfering signal, the system includes: consumer, electric wire netting the consumer with circuit and at least one brtterworth type low pass filter that the electric wire netting is connected, wherein, the consumer with it is used for the suppression to be connected with between at least one phase line in the three phase line of the circuit that the electric wire netting is connected and its neutral conductor consumer medium -high frequency harmonic produces the power line carrier communication signal and disturbs brtterworth type low pass filter. The utility model discloses a system passes through brtterworth type low pass filter can effectively eliminate the interfering signal in the power line carrier communication circuit.

Description

System for restraining interference signals of power utilization information acquisition system

Technical Field

The utility model relates to an electric power tech field especially relates to a system for restraining power consumption information acquisition system interference signal.

Background

The power utilization information acquisition system is a foundation for acquiring, processing and monitoring power utilization information of power consumers in real time and is an important component for building a unified and strong intelligent power grid. The electricity utilization information acquisition system can be physically divided into a main station, a communication channel and acquisition equipment according to the deployment position. The communication channel is a bridge and a link for connecting the terminal equipment and the main station of the acquisition system, and the communication channel adopted by the existing low-voltage meter reading concentrator is mainly a power line carrier. The power line carrier communication is a technology for transmitting an analog or digital signal at a high speed by a carrier method using an existing power line, and this communication method enables data transmission as long as a power line is present without newly setting up a network. However, high frequency harmonics are generated in transformers, variable frequency motors, elevators, power electronic equipment and the like, interference is generated on power line carrier communication, and the acquisition success rate of power utilization information is affected.

In order to suppress high-frequency harmonics, in the prior art, a bypass capacitor is additionally arranged between a power supply and a load, two poles of the capacitor are respectively connected with a phase line and a neutral line, and the high-frequency harmonics in the phase line flow to the neutral line through the capacitor and enter the ground, so that the interference on power line carrier communication signals of the power utilization information acquisition system is reduced.

However, when the capacitor is additionally arranged between the power supply and the load, the capacitor with different capacitance values needs to be repeatedly additionally arranged due to different harmonic frequency range generated by different electric equipment, then whether the power line carrier communication signal is interfered after the capacitor is additionally arranged is checked, and if the communication signal is normal, the capacitor with the corresponding capacitance value is proved to meet the requirement. The process is complicated, the randomness is high, various capacitors with different capacitance values need to be prepared on site, the working efficiency is reduced, and the working process for improving the success rate of power utilization information acquisition is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model provides a system for restrain power consumption information acquisition system interference signal to solve one or more disappearance among the prior art.

The utility model also provides a system for restrain power consumption information acquisition system interfering signal, the system includes: the system comprises electric equipment, a power grid, a circuit for connecting the electric equipment with the power grid and at least one Butterworth type low-pass filter; the Butterworth type low-pass filter is connected between at least one phase line of three phase lines of a circuit connected with the power grid and a neutral line of the circuit, and is used for inhibiting interference of high-frequency harmonic waves in the electric equipment on power line carrier communication signals.

In one embodiment, the butterworth-type low-pass filter includes an inductor and a capacitor selected according to an interference frequency band of a harmonic interference signal, the electric equipment generating the harmonic interference signal, a circuit connecting the electric equipment and the power grid, a set order, and an input end impedance realized by a coulter circuit.

In one embodiment, the butterworth-type low pass filter comprises: the first end button, the second end button, the first inductor, the first capacitor, the second inductor, the second capacitor, the third inductor and the load resistor; the circuit for connecting the electric equipment with the power grid comprises a phase line and a neutral line; one end of the first terminal button is connected with the phase line, the other end of the first terminal button is connected to one end of the second terminal button sequentially through the first inductor, the second inductor, the third inductor and the load resistor, and the other end of the second terminal button is connected with the neutral line; one end of the first capacitor is connected between the first inductor and the second inductor, and the other end of the first capacitor is connected between the second terminal button and the load resistor; one end of the second capacitor is connected between the second inductor and the third inductor, and the other end of the second capacitor is connected between the first capacitor and the load resistor.

The utility model discloses a system for restraining power consumption information acquisition system interfering signal can effectively eliminate the interference that the high frequency harmonic produced power line carrier communication signal among the consumer through at least one Butterworth type low pass filter. The Butterworth type low-pass filter is realized by adopting inductance and capacitance elements, is a low-pass filter of an analog circuit, does not need to carry out digital sampling and operation on signals relative to a digital filter, and is convenient to install and debug. The parameters of the inductor and the capacitor in the filter are further divided into consideration of relevant factors of all parts, including electric equipment, a connecting circuit and the order of the filter, and finally the Butterworth type low-pass filter is realized. The utility model discloses generate the Butterworth type low pass filter who is arranged in suppressing interference signal among the power line carrier communication specially in advance, install the Butterworth type low pass filter who realizes again between the power consumption equipment of electric wire netting and the easy high frequency interference signal that produces, can effectively restrain the interference that the high frequency harmonic produced power line carrier communication among the power consumption equipment, improve the collection success rate of power consumption information.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts. In the drawings:

fig. 1 is a schematic structural diagram of a system for suppressing interference signals of an electricity consumption information acquisition system according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a butterworth-type low-pass filter according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram of a two-port network of a butterworth-type low-pass filter with a power supply and a load according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a coler ladder circuit according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are described in further detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

The embodiment of the utility model provides a system and method for restraining power consumption information acquisition system interfering signal. The system and the method are based on a Butterworth type low-pass filter to inhibit interference of high-frequency harmonic waves in electric equipment on power line carrier communication signals.

Fig. 1 is a schematic structural diagram of a system for suppressing interference signals of an electricity information collection system according to an embodiment of the present invention. As shown in fig. 1, the system for suppressing the interference signal of the power consumption information acquisition system includes a power consumption device 110, a power grid 120, a circuit 130 for connecting the power consumption device to the power grid, and three butterworth-type low pass filters 140.

A butterworth low-pass filter 140 is connected between each of the phase lines A, B and C of the grid-connected circuit 130 and the neutral line N of the circuit 130, so as to suppress interference of high-frequency harmonics in the electric equipment 110 with the power line carrier communication signal in the circuit 130 by the butterworth low-pass filter 140.

Optionally, the system for suppressing the interference signal of the power consumption information acquisition system includes only one or two of the foregoing butterworth-type low-pass filters 140, and only one or two of the phase lines A, B and C of the circuit 130 are connected to the neutral line N of the circuit 130 through the butterworth-type low-pass filter 140, so as to suppress the interference generated by the power consumption device 110 on the power carrier communication signal on the phase line of the circuit 130 to which the butterworth-type low-pass filter 140 is connected.

The utility model discloses restrain power consumption information acquisition system interference signal's system leads to between at least one Butterworth type low pass filter lug connection to phase line and the neutral conductor, can effectively eliminate the interference that the high-frequency harmonic produced power line carrier communication signal among the consumer. Simple to operate for the work efficiency is high is gathered to the power consumption.

In an embodiment, as shown in fig. 1, the system for suppressing the interference signal of the power consumption information acquisition system, wherein the butterworth-type low-pass filter 140 includes at least one inductance element and at least one capacitance element, and parameters of the inductance element and the capacitance element are obtained by calculation and analysis according to an interference frequency band of the harmonic interference signal, the power consumption equipment 110 generating the harmonic interference signal, the circuit 130 connecting the power consumption equipment to the power grid, the set order of the butterworth-type low-pass filter, and the input impedance realized by the coulter circuit.

The embodiment of the utility model provides an in, according to interference frequency channel, consumer, connecting circuit, reasonable filter order and coulter ladder circuit, finally realize designing in advance out the butterworth type low pass filter who is arranged in inhibiting interference signal specially among the power line carrier communication, need not to install like the device of the condenser elimination interference signal among the prior art is repeated additional, can effectively eliminate the interference of consumer to power line carrier communication signal. The Butterworth type low-pass filter of the analog circuit is realized through the inductance and the capacitance element, digital sampling and operation on signals are not needed to be carried out like a digital filter, and the installation and debugging are convenient.

Fig. 2 is a schematic circuit diagram of a butterworth-type low-pass filter according to an embodiment of the present invention. As shown in fig. 2, in the above embodiments, the butterworth low pass filter 140 may include a first terminal 1, a second terminal 1', a first inductor L1, a first capacitor C2, a second inductor L3, a second capacitor C4, a third inductor L5, and a load resistor RL.

In combination with a phase line A, B, C and a neutral line N in the electric circuit 130 for connecting the electric equipment to the power grid shown in fig. 1, one end of the first terminal button 1 is connected with the phase line (a or B or C), the other end is connected to one end of the second terminal button 1 'through a first inductor L1, a second inductor L3, a third inductor L5 and a load resistor RL in sequence, and the other end of the second terminal button 1' is connected with the neutral line N; one end of the first capacitor C2 is connected between the first inductor L1 and the second inductor L3, and the other end is connected between the second terminal button 1' and the load resistor RL; one end of the second capacitor C4 is connected between the second inductor L3 and the third inductor L5, and the other end is connected between the first capacitor C2 and the load resistor RL;

the input end impedance determination is realized by the first inductor L1, the first capacitor C2, the second inductor L3, the second capacitor C4 and the third inductor L5 according to the interference frequency band of the harmonic interference signal, the electric equipment 110 generating the harmonic interference signal, the circuit 130 connecting the electric equipment with the power grid, the set order and the coulter circuit; the value of the load resistance RL is determined by the circuit 130 connecting the consumer to the grid.

The embodiment of the utility model provides an in, obtain reasonable inductance and capacitive element's parameter through interference frequency channel, consumer and connecting circuit analysis to combine the filtering function that coulter ladder circuit realized the butterworth type system function, the wave filter realization process is simple and convenient, and is good to power line carrier communication interference signal's filter effect.

Fig. 3 is a schematic circuit diagram of a two-port network of a butterworth-type low-pass filter with a power supply and a load according to an embodiment of the present invention. As shown in FIG. 3, the high frequency harmonic signal source has an internal resistor R_sThe high-frequency harmonic source voltage E_s(j ω) the signal spectrum provides an input voltage U for the Butterworth low pass filter 140₁(j ω) spectrum. Output voltage U of butterworth low pass filter 140₀(j ω) spectrum. Viewed from port 1-1', Butterworth-type low-pass filter 140 has an input impedance Z_in. A load resistor R is connected to a port 2-2' of the Butterworth low-pass filter 140_L. Each of the above frequency spectra has an angular frequency ω.

Output voltage U with high-frequency harmonic signal₀(j ω) and a high frequency harmonic source voltage E_s(j ω) as a system function, the frequency characteristic of the high frequency harmonic signal is:

$H\left(j\mathrm{\ω}\right)=\frac{U_0\left(j\mathrm{\ω}\right)}{E_s\left(j\mathrm{\ω}\right)}.---\left(1\right)$

establishing a module function | H (j ω) | ceiling based on the amplitude-frequency characteristic | H (j ω) | square of the system function²The calculation expression is as follows:

|H(jω)|²＝H(jω)H(-jω)。(2)

the mode function of the butterworth low-pass filter is:

${\left|H\left(j\mathrm{\ω}\right)\right|}^2=\frac{1}{1+{\left(\frac{\mathrm{\ω}}{{\mathrm{\ω}}_c}\right)}^{2N}}.---\left(3\right)$

wherein N represents the order of Butterworth type low-pass filter, N is an integer, and ω is_cThe cut-off angular frequency of the butterworth low-pass filter.

The complex frequency extension of the modulo function (formula (3)) is performed, i.e. the angular frequency j ω is replaced by the complex frequency s, so as to obtain:

$H\left(s\right)H(-s)=\frac{{\left({\mathrm{j\ω}}_c\right)}^{2N}}{s^{2N}+{\left({\mathrm{j\ω}}_c\right)}^{2N}}.---\left(4\right)$

all poles of the complex frequency extended module function (equation (4)) are:

$s_p={\mathrm{j\ω}}_c{(-1)}^{\frac{1}{2N}}={\mathrm{\ω}}_c{e}^{j\mathrm{\π}(\frac{1}{2}+\frac{2p-1}{2N})},p=1,2,...,2N.---\left(5\right)$

when p is 1, 2, …, N, the poles are evenly distributed in the left half plane of the complex plane; when p is N +1, N +2, …, 2N, the poles are evenly distributed in the right half of the complex plane.

In one embodiment, considering only the poles in the left half of the complex plane of the distribution, the system function that results in a butterworth-type low-pass filter is:

$H\left(s\right)=\frac{{{\mathrm{\ω}}_c}^N}{\underset{p=1}{\overset{N}{\Π}}(s-s_p)},---\left(6\right)$

wherein N is the above-mentioned set order, ω_cIs the above-mentioned cut-off angular frequency, s is a complex frequency, s_pIs the pole of the system function norm on the left half complex plane, s_pSpecifically, it is shown in formula (5).

The embodiment of the utility model provides an in, ask the system function through only considering the pole that distributes at the complex plane of half on the left side for the butterworth type low pass filter who designs becomes stable causal system.

Referring again to FIG. 3, the Butterworth-type low pass filter is a two-port circuit that terminates in a load resistor R at its output 2-2_LThen, it becomes a single-port circuit. The applicant considered that the two-port circuit of the butterworth-type low-pass filter is realized by a single-port circuit.

Fig. 4 is a schematic structural diagram of a coler ladder circuit according to an embodiment of the present invention. As shown in fig. 4, the coler ladder is a simple form of single port circuit.

First, as can be seen from fig. 4, the input impedance of the ladder circuit is:

$Z_{in}=Z_1+\frac{1}{Y_2+\frac{1}{Z_3+\frac{1}{Y_4+\frac{1}{Z_5+R_L}}}},---\left(7\right)$

wherein Z is_inIs the input impedance, Z₁、Z₃And Z₅Is the impedance of the string arm, Y₂And Y₄Is a parallel arm admittance.

Then, using the inductance element L₁、L₃And L₅Respectively realizing series arm impedance Z₁、Z₃And Z₅Using a capacitive element C₂And C₄Respectively realize parallel arm admittance Y₂And Y₄Then equation (7) can be expressed as:

$Z_{in}\left(s\right)={\mathrm{sL}}_1+\frac{1}{{\mathrm{sC}}_2+\frac{1}{{\mathrm{sL}}_3+\frac{1}{{\mathrm{sC}}_4+\frac{1}{{\mathrm{sL}}_5+R_L}}}},---\left(8\right)$

wherein Z is_k＝sL_kK is 1, 3 or 5, Y_k＝sC_kK is 2 or 4, and s is the complex frequency.

From the formula (8), it can be seen that the numerator polynomial order of the ladder circuit input impedance is higher than the denominator polynomial order by one order, and the applicant considers that, according to the above characteristics, the circuit structure and the parameters of the circuit elements of the butterworth low-pass filter are determined according to the input impedance.

Next, a circuit implementation of the passive LC analog/butterworth low pass filter in the embodiment of the present invention will be described. When the input impedance Z is combined with FIG. 3 and FIG. 4_in＝R_sIn time, i.e. when the circuit shown in fig. 4 is in a matched condition, the high frequency harmonic signal source E_sCan provide maximum input power P for the filter₁ ⁺I.e. by

$P_1^{+}=\frac{{\left|E_s\right|}^2}{4R_s},---\left(9\right)$

Wherein the input power P₁ ⁺Which may also be referred to as the incident power at the input of the filter.

At this time, the filter input terminal voltage U₁Comprises the following steps:

$U_1=U_1^{+}=\frac{1}{2}{E}_s,---\left(10\right)$

wherein,referred to as the incident voltage at the input of the filter.

When the input impedance Z_inIs not equal to the internal resistance R of the signal source_sTime, filter input terminal voltage U₁Comprises the following steps:

$U_1=\frac{Z_{in}}{Z_{in}+R_s}{E}_s.---\left(11\right)$

the applicant considers that the input impedance Z of the filter is reflected_inAnd the internal resistance R of the signal source_sDefining the reflected voltage at the input of the filterComprises the following steps:

$U_1^{-}=U_1-U_1^{+}=\frac{Z_{in}}{Z_{in}+R_s}{E}_s-\frac{1}{2}{E}_s=\frac{1}{2}\frac{Z_{in}-R_s}{Z_{in}+R_s}{E}_s.---\left(12\right)$

will reflect the voltageAnd incident voltageThe ratio is defined as the voltage reflection coefficient rho at the input of the filter₁(s), namely:

${\mathrm{\ρ}}_1\left(s\right)=\frac{U_1^{-}}{U_1^{+}}=\frac{Z_{in}\left(s\right)-R_s}{Z_{in}\left(s\right)+R_s}.---\left(13\right)$

in one embodiment, applicants contemplate that if the voltage reflection coefficient ρ is first determined₁(s) the input impedance Z of the filter input can be determined from equation (13)_in(s) is:

$Z_{in}\left(s\right)=\frac{1+{\mathrm{\ρ}}_1\left(s\right)}{1-{\mathrm{\ρ}}_1\left(s\right)}{R}_s,---\left(14\right)$

where s is the complex frequency, ρ₁(s) is the voltage reflection coefficient, R_sIs the internal resistance value of the high-frequency harmonic signal source.

As can be seen from equation (14), Z is required_in(s) obtaining the voltage reflection coefficient rho of the input end of the filter₁(s) the voltage reflection coefficient ρ in the embodiment of the present invention is explained below₁(s) solving method.

Voltage reflection coefficient rho according to equation (13)₁(s), the square of the voltage reflection coefficient can be obtained:

${\mathrm{\ρ}}_1^2\left(s\right)={\left(\frac{U_1^{-}}{U_1^{+}}\right)}^2=\frac{{\left(U_1^{-}\right)}^2}{\frac{1}{4}{\left(E_s\right)}^2}=\frac{\frac{{\left(U_1^{-}\right)}^2}{R_s}}{\frac{{\left(E_s\right)}^2}{4R_s}}=\frac{P_1^{-}}{P_1^{+}},---\left(15\right)$

in the formula (15), P is₁ ^-Referred to as reflected power generated by impedance mismatch at the input of the filter. Since the LC circuit is passive and lossless, the input power P at the input of the filter₁Should equal the load power P at the output of the filter_LInput power P₁Incident power P₁ ⁺And reflected power P₁ ^-The relationship between them is:

P₁ ^-＝P₁ ⁺-P₁＝P₁ ⁺-P_L。(16)

substituting equation (16) into equation (15) yields the square of the voltage reflection coefficient as:

${\mathrm{\ρ}}_1^2\left(s\right)=\frac{P_1^{-}}{P_1^{+}}=1-\frac{P_L}{P_1^{+}}=1-\frac{\frac{U_0^2}{R_L}}{\frac{E_s^2}{4R_s}}=1-\frac{4R_s}{R_L}{\left(\frac{U_0}{E_s}\right)}^2=1-\frac{4R_s}{R_L}{H}^2\left(s\right),---\left(17\right)$

in one embodiment, equation (17) is modified to have a voltage reflection coefficient modulo:

${\mathrm{\ρ}}_1\left(s\right){\mathrm{\ρ}}_1(-s)=1-\frac{4R_s}{R_L}H\left(s\right)H(-s),---\left(18\right)$

where ρ is₁(s) is the voltage reflection coefficient, ρ₁(-s) is the complex conjugate of the voltage reflection coefficient, s is the complex frequency, R_sIs said internal resistance value, R_LIs the load resistance value, H(s) is the system function, and H (-s) is the complex conjugate of the system function.

As can be seen from equation (18), the butterworth-type (passive LC analog) low-pass filter is implemented as follows:

(1) substituting the system function H(s) of the Butterworth type low-pass filter into an equation (18), and calculating the voltage reflection coefficient modulus rho₁(s)ρ₁All poles and zeros of (-s);

(2) the voltage reflection coefficient modulus rho₁(s)ρ₁All poles and zeros of (-s) are divided into two categories according to the left half-plane and the right half-plane in the complex plane;

(3) reflection coefficient rho₁All poles of(s) should be distributed in the left half of the complex plane, while the reflection coefficient ρ is such that the Butterworth low-pass filter has a minimum phase₁All zeros of(s) are also distributed in the left half plane of the complex plane. Thus, the reflection coefficient rho is constructed according to the poles and zeros distributed in the left half plane of the complex plane₁(s) to obtain a Butterworth type low pass filter with stable causal system.

(4) Reflection coefficient of voltage ρ₁(s) is substituted into the formula (14) to obtain the input end impedance Z of the Butterworth type low-pass filter_in(s) and implementing input impedance Z with a Coule ladder circuit_in(s), a Butterworth type low pass filter can be realized.

The utility model discloses a system for restraining power consumption information acquisition system interfering signal can effectively eliminate the interference that the high frequency harmonic produced power line carrier communication signal among the consumer through at least one Butterworth type low pass filter. The Butterworth type low-pass filter is realized by adopting inductance and capacitance elements, is a low-pass filter of an analog circuit, does not need to carry out digital sampling and operation on signals relative to a digital filter, and is convenient to install and debug. The parameters of the inductor and the capacitor in the filter are further divided into consideration of relevant factors of all parts, including electric equipment, a connecting circuit and the order of the filter, and finally the Butterworth type low-pass filter is realized. The utility model discloses generate the Butterworth type low pass filter who is arranged in suppressing interference signal among the power line carrier communication specially in advance, install the Butterworth type low pass filter who realizes again between the power consumption equipment of electric wire netting and the easy high frequency interference signal that produces, can effectively restrain the interference that the high frequency harmonic produced power line carrier communication among the power consumption equipment, improve the collection success rate of power consumption information.

The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (3)

1. A system for suppressing interference signals in a power consumption information collection system, the system comprising: the system comprises electric equipment, a power grid, a circuit for connecting the electric equipment with the power grid and at least one Butterworth type low-pass filter;

the Butterworth type low-pass filter is connected between at least one phase line of three phase lines of a circuit connected with the power grid and a neutral line of the circuit, and is used for inhibiting interference of high-frequency harmonic waves in the electric equipment on power line carrier communication signals.

2. The system for suppressing interference signals in a power consumption information acquisition system according to claim 1, wherein the butterworth-type low pass filter comprises an inductor and a capacitor selected according to an interference frequency band of a harmonic interference signal, the electric device generating the harmonic interference signal, a circuit connecting the electric device and the power grid, a set order, and an input impedance realized by a coulter circuit.

3. The system for suppressing interference signals in a power consumption information collection system of claim 2,

the butterworth-type low pass filter includes: the first end button, the second end button, the first inductor, the first capacitor, the second inductor, the second capacitor, the third inductor and the load resistor; the circuit for connecting the electric equipment with the power grid comprises a phase line and a neutral line;

one end of the first terminal button is connected with the phase line, the other end of the first terminal button is connected to one end of the second terminal button sequentially through the first inductor, the second inductor, the third inductor and the load resistor, and the other end of the second terminal button is connected with the neutral line; one end of the first capacitor is connected between the first inductor and the second inductor, and the other end of the first capacitor is connected between the second terminal button and the load resistor; one end of the second capacitor is connected between the second inductor and the third inductor, and the other end of the second capacitor is connected between the first capacitor and the load resistor.